Um guia de cultivo passo a passo, da sementeira à colheita.
pH ideal 6.0 to 6.8Temperatura ideal 22 to 32 °CCompasso 50 cm in the row, 100 cm between rows
Sementeira
Sow in individual pots three to four weeks before planting out, two or three centimetres deep, with the compost between 25 °C and 30 °C. After pepper it is the seed that demands most heat to germinate: below 20 °C it simply will not come up. Transplant with the root ball intact, because the roots are unforgiving. Plant only once the soil is steadily above 18 °C. It carries separate male and female flowers on the same plant and depends on insects for fruit set. The first flowers are all male and set no fruit, which alarms many gardeners for no reason. If small fruits shrivel and drop, the problem is a shortage of pollinators: sow flowers nearby, avoid spraying during flowering, or hand pollinate early in the morning with a brush. This variety makes long trailing vines. You can let it run on the ground, allowing two to three metres per plant, or train it up a solid vertical support, which saves space, keeps the fruit clean and greatly reduces leaf disease. If you train it upwards and the fruits are heavy, support each one with a net or a cloth sling tied to the frame.
Solo
It wants sandy or loamy soil, deep, very free draining and quick to warm, with a pH between 6.0 and 6.8. Enrich the planting hole with mature compost. In heavy cold soil the crop rarely pays; there, use a raised bed with a dark mulch.
Clima
It needs strong prolonged heat, between 22 °C and 32 °C, full sun and a season of three to four months without cold. It is the crop of choice for inland Portugal and Spain and southern France. On the cool Atlantic coast and in Germany it only pays under glass or in a tunnel, and even then with small early varieties. On the Portuguese coast the crop starts slowly because nights stay cool and morning fog keeps the leaves wet for hours, so pick the sunniest spot you have, shelter it from wind and space the plants generously so air moves through. Inland in Portugal and Spain heat rather than cold is the limiting factor: in weeks above 35 °C the plant stalls and light shade over midday pays for itself. In France outdoor growing is reliable from the centre southwards, while in northern France and in Germany a greenhouse, a polytunnel or a warm south facing wall makes the difference, and planting out should wait until after the mid May cold snap. Where summers are short, always choose the shorter cycle varieties and start them early in a heated tray. In Italy it is an easy crop: in the centre and south plant from April onwards and the only real care is light shade through the July and August heat; in the Po valley and the north wait for the late frosts to pass and pick the sunniest spot you have.
Fertilização
This is a hungry crop. Work two to three kilos of well rotted compost or mature manure into each square metre before planting and add a handful of bone meal or wood ash to top up phosphorus and potassium. Once growth is away, feed with a liquid organic fertiliser every two or three weeks, moving from a balanced formula to a higher potassium one as cropping begins. Avoid excess nitrogen, which gives lush leaves, a poor crop and a lot of aphids.
Rega
Water generously through growth and fruit fill and stop watering for the final two or three weeks. That is the golden rule for watermelon: water to the end means watery fruit with no sweetness and a tendency to split. Always water at the base, ideally by drip.
Controlo de Infestantes
The critical period is the first month, before the foliage covers the ground. Hand weed in that phase and, once the vines start to run, stop disturbing the soil: from then on the plant smothers weeds itself. A straw mulch under the foliage keeps the fruit clean and dry and greatly reduces losses to rot where fruit touches the soil.
Controlo de Pragas
The main pests are aphids, red spider mite, thrips and whitefly, and on young plants slugs and snails, which can cut down a newly emerged seedling in one night. Protect the seedlings with a cut bottle or an ash barrier for the first weeks. Against aphids and whitefly use potassium soap in the late afternoon; against red spider mite, which appears in dry heat, wet the leaves in the morning and use neem oil. Also watch for stem borers at the base of the plant and beetle larvae in the roots.
Doenças
Powdery mildew is practically unavoidable and shows as white dust on the upper leaf surface, above all from midsummer on. It is checked with potassium bicarbonate or sulphur applied at the first signs, together with removal of old leaves and good airflow. Cucurbit downy mildew gives angular yellow patches bounded by the veins and thrives in coastal humidity. Water at the base of the plant, never at night and never over the leaves. Anthracnose and collar rot appear in waterlogged soil. Use a four year rotation and clear all crop debris at the end of the season, because that is where the fungi overwinter.
Colheita
Three signs together mark the point: the tendril nearest the fruit is dry and brown, the ground spot has gone from white to creamy yellow, and the sound when tapped is dull rather than metallic. Watermelon does not ripen after picking, so cutting too early is irreversible. Cut with a knife leaving a few centimetres of stalk. Allow about 70 to 80 days from transplanting to the first harvest of this variety. The reference colour is pale green skin with green stripes and orange flesh, and that is what tells you it is ready.
